1. Field of the Description
The present invention relates, in general, to projecting or displaying video/animated or still three dimensional (3D) images, and, more particularly, to autostereoscopy methods and systems for providing glasses-free 3D using a transparent multi-view mask or “magic window” capable of selectively blocking, filtering, passing, or even adding light to objects viewed through the multi-view mask or magic window.
2. Relevant Background
There are numerous entertainment and other settings where it is desirable to create unique visual displays to entertain and excite viewers. For example, theme or amusement parks may include rides or walk-through attractions where guests (or “viewers”) are entertained by a unique visual effect or illusion. Often, it is desirable to create a display with three dimensional (3D) images, and, even more desirable for many entertainment facility operators is to provide the 3D display without requiring the viewer to wear special headgear or glasses, e.g., using autostereoscopy or similar techniques.
With this in mind, Pepper's ghost is an illusionary technique used by magicians, by ride or attraction designers, and others to produce a 3D illusion of a latent or ghost-like image. Using a simple piece of plate glass and special lighting techniques, Pepper's ghost systems can make objects appear and disappear within a scene or room. Generally, these systems include a main room or scene that is readily viewed by a guest or viewer and a hidden room that is not visible to the viewer, and both rooms may be identical in their physical structure including furniture and other objects except the hidden room may include additional objects or characters such as a ghost. A large piece of glass or a half-silvered mirror is situated between the viewer and the scene at an angle, such as at about 45 degrees. When the main, room is lit and the hidden room is darkened, the viewer only sees the main room as the hidden room does not reflect from the glass and the sheet of glass is itself hard to see as it typically extends across the entire view of the main room.
Pepper's ghost then becomes very visible to the viewer when the entire hidden room or portions such as the ghost or other character are brightly lit. Since only a portion of the light cast upon the ghost or other objects in the hidden room is reflected from the glass, the reflected images appear as latent or ghostly images relative to the objects in the main room (e.g., the reflected images or images superimposed in the visible room may appear to float). The Pepper's ghost image is a 3D image that may be a still image or animation may be provided such as with animatronics providing the “ghost” or by placing a live actor in the hidden room. In many current systems, a 2D display is used as it is more dynamic and controllable and does not require a live actor or expensive animatronics. In a broad sense, then, the Pepper's ghost systems may be thought of as implementing autostereoscopy, which is generally a method of displaying 3D images that can be viewed without the use of headgear or glasses on the part of the user.
From the above discussion, it can be understood that a traditional Pepper's Ghost illusion uses a partially reflecting pane of glass or beam splitter to overlay a physical object's reflection onto a real world scene. The reflected physical object appears three dimensional and appears to occupy space in the real world scene. Unfortunately, the reflected physical object also appears translucent and ghostly and does not cast a shadow. Efforts have been made to provide dynamic masks within the real world scene to block the background and make the reflected object appear opaque and to cast a true shadow.
However, for both a physical object and a dimensional display, the silhouette changes according to a viewer's view point. Similarly, a cast shadow changes according to light source direction. In one application, a dynamic mask produced from a 2D display is used to create a 3D display but the 2D display can only produce a correct silhouette mask for one view point. For example, the 3D display may be improved with a proper silhouette and opacity of displayed 3D objects, but it may only appear correct or be effective when viewed from one positioned (e.g., a viewer with an orthogonal or direct-on view point) and the 3D display loses its correctness when the viewer moves to the left or right and changes their point of view. Similarly, the cast shadow would be that of a flat 2D silhouette, and the shadow would lose its correctness if the light source direction changed.
Hence, there remains a need for improved visual display techniques and systems for creating or projecting 3D images. Preferably, such an advanced 3D display system would provide a higher contrast, solid or opaque-appearing, and 3D dimensional image without requiring a viewer to wear special head gear or glasses. Further, it is preferred that the display system produces a 3D image that may be viewed from multiple points of view, e.g., the system may be considered a “multi-view” 3D display system.